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----- Original Message ----- From: "Donna Crossland" <dcrossland@eastlink.ca> To: <naturens@chebucto.ns.ca> Sent: Sunday, January 10, 2016 10:43 PM Subject: RE: [NatureNS] re Red Herring & Forestry <snip> I would hazard a guess that the forests I've > read that are dying all at once are white spruce (hit hard by spruce bark > beetle). That situation does not speak for the rest. <snip> Dear All, Jan 12, 2016 I wish to advance a few words in honor of Roland. I never had the pleasure of meeting him but based on his advocacy of a working "crap detector" I felt that he was a genuine naturalist and, if one had to get lost in the jungle, a desirable companion in such adversity. So far as I am aware he was the first person on Naturens to use that term and as you gain experience in the maintenance and use of a Crap Detector you will be astonished at the pile of 'information' from authoritative sources that is selected for rejection. The gospel that White Spruce is "hit hard by spruce bark beetle" is a good example. It is relevant to ask why they get hit one year and not previous years or why these three trees are riddled and a nearby one is fine. If you look at the weather pattern associated with a year of 'infestation' you will usually find an unusually dry period in the previous or current year and if you consider the setting of the spared tree it will usually have more elbow room. And most importantly one should recognize that a tree, whether it be a White Spruce, Red Spruce, Ash,... is not a constant but a variate which will be a function of weather, soil... conditions past and present. In general Foresters and Entomologists do not have a working and exercised knowledge of Plant Physiology. It likely helps to have a woodpile in the yard containing Spruce wood but if you cut a live healthy branch from a healthy Spruce during the growing season, and bring the branch home so it can be readily checked for activity, you will usually see Scolytid and Clerid activity within two days of warm weather. The general conclusion which I have reached is that 'infestations' of all insects which feed in bark or wood are triggered by water stress or damage which leads to water stress. The exact mechanism is not clear but in conifers it may be related to resin flow. It could be that no eggs are deposited in healthy trees or that no eggs survive in healthy trees. If conifer bark is cut with a sharp knife on a warm day when soil water is ample then there will usually be a copious and rapid flow of thin resin. If a similar cut is made after a long period of no rainfall then resin flow, if any, will be very slow and viscous. Similar consideration apply to Ash which of course lacks resin so in non-coniferous trees the mechanism may involve turgor pressure when an attempt is made to deposit an egg in live tissue, turgor pressure when a larva first enter live tissue...or something more subtle. But cut a healthy branch off of a healthy Ash in mid May and within a few days (sometimes hours) there will be incoming flights of a small weevil (Hylesinus aculeatus); best when warm & calm. Once again it likely helps to have aged Ash firewood nearby. In Memory of Roland and his Crap Detector, Dave Webster, Kentville > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2016.0.7294 / Virus Database: 4489/11377 - Release Date: 01/11/16 >
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